Which mathematical concept indicates a value that does not change?

The correct answer is the term that refers to a specific value that remains the same regardless of the circumstances or the values assigned to other elements within a mathematical context. A constant is a quantity without variation; it does not change. For instance, in an equation like ( y = 3x + 5 ), the number 5 is a constant because it consistently represents the same value in this equation, whereas ( x ) is a variable that can take on different values.

In contrast, a variable is a symbol used to represent a number that can change or vary. An expression is a combination of numbers, variables, and operations that represents a value, but it can contain constants as well as variables. Lastly, a measure typically refers to the quantitative assessment of a property, which may involve variables and constants but does not specifically denote a value that remains unchanged. Therefore, a constant is uniquely defined as a stable value in mathematical expressions and equations.